Recapturing the mojo: AMD’s Radeon HD 7970 GHz Edition

Stress-testing AMD's latest video card.

Batman: Arkham City

We did a little Batman-style free running through the rooftops of Gotham for this one.
We're used to seeing those latency spikes in our Arkham City test sequence. We're moving through a very large and detailed cityscape, and the game engine has to stream in new areas as we glide into them.
Remember what I said about karmic payback? Here's an excellent game that happens to run better on GeForce cards—and Nvidia worked with developer Rocksteady Studios on it.
The Radeons' 99th percentile frame times are relatively high given their FPS averages; even the 7970 GHz Edition falls behind the GeForce GTX 570. Why?
The Radeon's latency curves shoot upward for the last 5-7% of frames. You can spot the problem in the plots up above. Although the plots for the GeForces show quite a few latency spikes, the spikes are more frequent on the Radeons. That extra helping of long frame times puts the Radeons at a disadvantage.
Our measure of "badness" captures the scope of the problem. The 7900-series Radeons spend two to three times as long working on especially high-latency frames as the GeForces do. Interestingly, though, the 7970 GHz Edition avoids these slowdowns much more effectively than the stock 7970 and XFX 7950 do. Perhaps the new, more aggressive PowerTune algorithm is paying off here.